1. Field of the Invention
The invention relates to a roller bearing cage that retains, for example, cylindrical rollers, tapered rollers, convex rollers, or the like, and also relates to a roller bearing.
2. Description of Related Art
A roller bearing cage is, for example, described in Japanese Patent Application Publication No. 2007-100738 (JP-A-2007-100738).
The roller bearing cage includes a plurality of spacers. The spacers are arranged along the same circle. Each spacer includes a cage bar, a first axial movement restricting portion and a second axial movement restricting portion. The cage bar extends in the axial direction of the roller bearing. In addition, the first axial movement restricting portion extends from one end portion of the cage bar in the axial direction toward one side in the circumferential direction, and the second axial movement restricting portion extends from the other end portion of the cage bar in the axial direction toward the other side in the circumferential direction.
In a state where the roller bearing cage is assembled to the roller bearing, the first axial movement restricting portion of each spacer axially faces the second axial movement restricting portion of the spacer adjacent to the above spacer in the circumferential direction.
The roller bearing cage forms a substantially annular pocket by the cage bar of the spacer, the first axial movement restricting portion of that spacer, the cage bar of the spacer adjacent to that spacer and the second movement restricting portion of the adjacent spacer to accommodate a roller in that pocket.
Because the roller bearing cage is formed of the plurality of spacers, even when the roller bearing is a large-sized bearing of which an annular cage is difficult to be manufactured by pressing, each spacer may be formed by pressing, so a roller bearing cage for a large-sized bearing may be easily manufactured at low cost.
However, in the above roller bearing cage, when lead and lag of rollers based on variations in the roller size, or the like, occur, the distance between a spacer and a spacer adjacent to that spacer locally increases and, as a result, the spacers may slip off.
In addition, it is difficult to adjust the positions of each spacer and a spacer adjacent to that spacer, and it is difficult to assemble the rollers, the roller bearing cage and inner and outer rings together.